Will measure cerebral blood flow (CBF) and cerebral oxygen consumption (CMRO2) and muscle protein catabolism and serum atrial natriuretic peptide (ANP), endothelin, serum and urinary cGMP, nitrates and nitrites prior to and following administration of E.Coli endotoxin (2-4ng/kg). Hypothesize that IV-administered endotoxin will increase CBF, CMRO2 and muscle protein catabolism and will result in increase in above vasodilators. Endotoxin has been previously administered to over 200 volunteers without adverse effects in other research institutions.